Respiratory Syncytial Virus (RSV) is the second leading cause of hospitalization in children worldwide and has been increasing appreciated as a cause of hospitalization and death in the elderly. Recent studies have shown that polyvalent vaccine formulations, mixture of antigens derived from distinct pathogen variants, can induce antibodies to regions conserved between those variants We hypothesize that polyvalent antigen RSV vaccine formulations will increase antibody to regions conserved between the antigens. By drawing on the natural variability that exists among RSV variants, we aim to study the effect that polyvalent RSV G or F antigen formulations have on the immune response. We will test if antibodies are enhanced towards regions conserved between the viral proteins with the polyvalent formulation. Aim 1. Determining the Effect of Polyvalent RSV Vaccine Formulations on Humoral Immunity using Computer Simulations. We hypothesize that RSV polyvalent vaccine formulations consisting of different combinations of G or F-protein antigens will increase the antibody response to conserved regions between the antigens. We will evaluate different vaccine formulations using a computational framework of virus/host- interaction (ssMod.v2). We will test for differences in antibody specificity between polyvalent and monovalent formulations in the framework. Antibody cross-reactivity and protection against RSV challenge will also be evaluated. Aim 2. Comparison of the Host Immune Response to Polyvalent Vaccine Formulations in Mice. We hypothesize that murine immunization with a mRNA-LNP vaccine comprising polyvalent antigen formulations will induce antibodies and immune cells specific to regions conserved between the antigens. mRNA-LNPs will be constructed using cap-1, codon-optimized, structure-stabilized mRNA, encoding G or F from A2 or B1 RSV variants and will be encapsulated using ionizable cationic lipids. Groups of mice will be immunized with either Aim 3. Test if RSV Polyvalent Vaccine Formulation Improves Protection from RSV Disease. We hypothesize that vaccine formulations containing polyvalent mixtures of G or F antigens will increase the extent of protection against RSV disease compared to monovalent formulations. Using different mixtures of mRNA- LNP, we will test the ability of polyvalent vaccines to protect against disease severity using a murine model of RSV challenge. The neutralizing antibody titer of the sera will be tested using a primary human lung epithelial cell RSV-neutralization assay. Monovalent and polyvalent vaccine formulations will be compared by testing for differences between infection and disease severity outcomes.

Narrative The development of vaccines against common respiratory viruses, such as RSV, remains challenging. Polyvalent mRNA-lipid-nanoparticle vaccines offer a potential solution. Here we propose test the effect polyvalent RSV vaccines have on adaptive immune response.